Electronic component

BACKGROUND OF THE INVENTION

p-00021. Field of the Invention

p-0003The present invention relates to an electronic component, and more particularly, to an electronic component including an external electrode made of a plated material and formed by plating.

p-00042. Description of the Related Art

p-0005As a related-art electronic component, there is known a multilayer electronic component disclosed in, e.g., International Publication No. 2007/049456. The disclosed multilayer electronic component includes a laminate, internal electrodes, and external electrodes. The laminate is formed by laminating (stacking) a plurality of insulator layers. The internal electrodes define a capacitor and are exposed at an end surface of the laminate. The external electrodes are each made of an electrolytic plating deposit and are disposed to directly cover portions of the internal electrode, which are exposed from the laminate.

p-0006However, as described below, the multilayer electronic component disclosed in International Publication No. 2007/049456 has a problem in that the external electrodes are apt to peel off from the laminate. As an electronic component other than the multilayer electronic component described above, there is known, for example, an electronic component including an external electrode that is formed by coating an electroconductive paste over an end surface of a laminate. The electroconductive paste is made of metal and glass. The glass serves as an adhesive. More specifically, when the external electrode is fired, the glass is softened and then coagulated, whereby the external electrode is fixed to the laminate. Therefore, the external electrode is relatively hard to peel off from the laminate.

p-0007On the other hand, in the multilayer electronic component disclosed in International Publication No. 2007/049456, because the external electrode is formed by plating, the external electrode contains no glass. Accordingly, the external electrode of the multilayer electronic component disclosed in International Publication No. 2007/049456 is fixed to the laminate with a reduced strength as compared to the external electrode that is formed using the electroconductive paste. Therefore, in the electronic component disclosed in International Publication No. 2007/049456, the external electrode is more apt to peel off from the laminate than in the electronic component that includes the external electrode formed by using the electroconductive paste.

SUMMARY OF THE INVENTION

p-0008To overcome the problems described above, preferred embodiments of the present invention provide an electronic component, which can effectively avoid an external electrode, which is formed by plating, from being peeled off from a laminate.

p-0009According to a preferred embodiment of the present invention, an electronic component preferably includes a laminate including a plurality of laminated insulator layers and a mounting surface defined by outer edges of the plurality of laminated insulator layers, the outer edges being continuously located adjacent to each other, inner conductors disposed on the insulator layers and including exposed portions that are exposed at the mounting surface between the insulator layers, and an external electrode disposed on an surface of the laminate, the external electrode including a first electroconductive layer disposed on the mounting surface to directly cover the exposed portions and made of a plated material, and a second electroconductive layer covering at least a portion of the first electroconductive layer, covering partial surfaces of the laminate, and made of a material including metal and one of glass and resin.

p-0010With the above-described preferred embodiment of the present invention, the external electrode made of plated material and formed by plating can be effectively prevented from being peeled off from the laminate.

p-0011The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0012<figref idrefs="DRAWINGS">FIG. 1</figref> is an external perspective view of an electronic component according to a preferred embodiment of the present invention.

p-0013<figref idrefs="DRAWINGS">FIG. 2</figref> is a perspective view of the electronic component shown in <figref idrefs="DRAWINGS">FIG. 1</figref> with the omission of electroconductive layers of the electronic component.

p-0014<figref idrefs="DRAWINGS">FIG. 3</figref> is an exploded perspective view of a laminate in the electronic component shown in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0015<figref idrefs="DRAWINGS">FIG. 4</figref> is a plan view illustrating the electronic component shown in <figref idrefs="DRAWINGS">FIG. 1</figref> while seeing through the electronic component from above in a laminating direction.

p-0016<figref idrefs="DRAWINGS">FIG. 5</figref> is a plan view illustrating an electronic component according to a first modification of a preferred embodiment of the present invention while seeing through the electronic component from above in a laminating direction.

p-0017<figref idrefs="DRAWINGS">FIG. 6</figref> is a plan view illustrating an electronic component according to a second modification of a preferred embodiment of the present invention while seeing through the electronic component from above in a laminating direction.

p-0018<figref idrefs="DRAWINGS">FIG. 7</figref> is a plan view illustrating an electronic component according to a third modification of a preferred embodiment of the present invention while seeing through the electronic component from above in a laminating direction.

p-0019<figref idrefs="DRAWINGS">FIG. 8</figref> is a plan view illustrating an electronic component according to a fourth modification of a preferred embodiment of the present invention while seeing through the electronic component from above in a laminating direction.

p-0020<figref idrefs="DRAWINGS">FIG. 9</figref> is a plan view illustrating an electronic component according to a fifth modification of a preferred embodiment of the present invention while seeing through the electronic component from above in a laminating direction.

p-0021<figref idrefs="DRAWINGS">FIG. 10</figref> is a plan view illustrating an electronic component according to a sixth modification of a preferred embodiment of the present invention while seeing through the electronic component from above in a laminating direction.

p-0022<figref idrefs="DRAWINGS">FIG. 11</figref> is a plan view illustrating an electronic component according to a seventh modification of a preferred embodiment of the present invention while seeing through the electronic component from above in a laminating direction.

p-0023<figref idrefs="DRAWINGS">FIG. 12</figref> is a plan view illustrating an electronic component according to another preferred embodiment while seeing through the electronic component from above in a laminating direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

p-0024An electronic component according to preferred embodiments of the present invention will be described below with reference to the drawings.

p-0025The construction of the electronic component is described with reference to the drawings. <figref idrefs="DRAWINGS">FIG. 1</figref> is an external perspective view of an electronic component <b>10</b> according to a preferred embodiment of the present invention. <figref idrefs="DRAWINGS">FIG. 2</figref> is a perspective view of the electronic component <b>10</b> with the omission of electroconductive layers <b>14</b><i>a </i>and <b>14</b><i>b </i>defining portions of external electrodes <b>30</b><i>a </i>and <b>30</b><i>b </i>of the electronic component <b>10</b>. <figref idrefs="DRAWINGS">FIG. 3</figref> is an exploded perspective view of a laminate <b>11</b> in the electronic component <b>10</b>. <figref idrefs="DRAWINGS">FIG. 4</figref> is a plan view illustrating the electronic component <b>10</b> while seeing through the electronic component <b>10</b> from above in a laminating direction. <figref idrefs="DRAWINGS">FIG. 4</figref> further illustrates a cross-sectional structure of the electronic component <b>10</b> in an enlarged view. In the following description, the laminating direction of the laminate <b>11</b> is defined as a y-axis direction. The lengthwise direction of the laminate <b>11</b> when viewing the laminate <b>11</b> in the y-axis direction is defined as an x-axis direction. The widthwise direction of the laminate <b>11</b> when viewing the laminate <b>11</b> in the y-axis direction is defined as a z-axis direction.

p-0026The electronic component <b>10</b> is a preferably chip capacitor. As illustrated in <figref idrefs="DRAWINGS">FIGS. 1 to 3</figref>, the electronic component <b>10</b> includes the laminate <b>11</b>, external electrodes <b>30</b> (<b>30</b><i>a</i>, <b>30</b><i>b</i>), and a capacitor C (see <figref idrefs="DRAWINGS">FIG. 3</figref>).

p-0027The laminate <b>11</b> preferably has a substantially rectangular parallelepiped shape, for example. As illustrated in <figref idrefs="DRAWINGS">FIG. 2</figref>, the laminate <b>11</b> includes side surfaces S<b>1</b> and S<b>2</b>, end surfaces S<b>3</b> and S<b>4</b>, an upper surface S<b>5</b>, and a lower surface S<b>6</b>. Corners and ridges of the laminate <b>11</b> are preferably rounded by chamfering, for example. In the following description, as illustrated in <figref idrefs="DRAWINGS">FIG. 2</figref>, a surface of the laminate <b>11</b> facing the positive direction side in the y-axis direction is denoted as the side surface S<b>1</b>, and a surface thereof facing the negative direction side in the y-axis direction is denoted as the side surface S<b>2</b>. Also, a surface of the laminate <b>11</b> facing the negative direction side in the x-axis direction is denoted as the end surface S<b>3</b>, and a surface thereof facing the positive direction side in the x-axis direction is denoted as the end surface S<b>4</b>. Further, a surface of the laminate <b>11</b> facing the positive direction side in the z-axis direction is denoted as the upper surface S<b>5</b>, and a surface thereof facing the negative direction side in the z-axis direction is denoted as the lower surface S<b>6</b>. The lower surface S<b>6</b> defines a mounting surface that is arranged to face a circuit board when the electronic component <b>10</b> is mounted to the circuit board.

p-0028As illustrated in <figref idrefs="DRAWINGS">FIG. 3</figref>, the laminate <b>11</b> includes a plurality of laminated ceramic layers (insulator layers) <b>16</b>. The ceramic layers <b>16</b> are each preferably substantially rectangular and made of a dielectric ceramic, for example. Examples of the dielectric ceramic are BaTiO₃, CaTiO₃, SrTiO₃, and CaZrO₃. The dielectric ceramic may preferably include at least one of those materials as a main component and a Mn compound, a Fe compound, a Cr compound, a Co compound, or a Ni compound, for example, as an accessory component. The thickness of the ceramic layer <b>16</b> is preferably in a range from about 0.5 μm to about 10 μm, for example. In the following description, a principal surface of the ceramic layer <b>16</b> on the positive direction side in the y-axis direction is denoted as a front surface, and a principal surface of the ceramic layer <b>16</b> on the negative direction side in the y-axis direction is denoted as a rear surface.

p-0029Thus, the side surface S<b>1</b> of the laminate <b>11</b> defines the front surface of the ceramic layer <b>16</b>, which is located farthest on the positive direction side in the y-axis direction. The side surface S<b>2</b> of the laminate <b>11</b> is defined the rear surface of the ceramic layer <b>16</b>, which is located farthest on the negative direction side in the y-axis direction. Also, the end surface S<b>3</b> is defined by shorter sides (outer edges) of the plurality ceramic layers <b>16</b>, which are continuously arranged adjacent to each other on the negative direction side in the x-axis direction. The end surface S<b>4</b> is defined by shorter sides (outer edges) of the plurality ceramic layers <b>16</b>, which are continuously arranged adjacent to each other on the positive direction side in the x-axis direction. The upper surface S<b>5</b> is defined by longer sides (outer edges) of the plurality of ceramic layers <b>16</b>, which are continuously arranged adjacent to each other on the positive direction side in the z-axis direction. The lower surface S<b>6</b> is defined by longer sides (outer edges) of the plural ceramic layers <b>16</b>, which are continuously arranged adjacent to each other on the negative direction side in the z-axis direction.

p-0030As illustrated in <figref idrefs="DRAWINGS">FIG. 3</figref>, the capacitor C includes capacitor conductors (inner conductors) <b>18</b><i>a</i>, <b>18</b><i>b </i>that are included in the laminate <b>11</b>. Preferably, each of the capacitor conductors <b>18</b> is made of an electroconductive material, e.g., Ni, Cu, Ag, Pd, an Ag—Pd alloy, or Au, and has a thickness in a range of about 0.3 μm to about 2.0 μm, for example.

p-0031The capacitor conductor <b>18</b><i>a </i>is disposed on a surface of the ceramic layer <b>16</b> and includes a capacitor portion <b>20</b><i>a </i>and lead portions <b>22</b><i>a </i>and <b>24</b><i>a</i>. The capacitor portion <b>20</b><i>a </i>is preferably substantially rectangular and is disposed inward of outer edges of the ceramic layer <b>16</b> without extending to the outer edges. The lead portion <b>22</b><i>a </i>extends toward the negative direction side in the z-axis direction from a region of a longer side of the capacitor portion <b>20</b><i>a </i>on the negative direction side in the z-axis direction, which region is located near an end of the longer side thereof on the negative direction side in the x-axis direction. Thus, the lead portion <b>22</b><i>a </i>extends to the longer side of the ceramic layer <b>16</b> on the negative direction side in the z-axis direction. The lead portion <b>22</b><i>a </i>includes, at its distal end on the negative direction side in the z-axis direction, an exposed portion <b>26</b><i>a </i>that is exposed between two adjacent ceramic layers <b>16</b> at the lower surface S<b>6</b> of the laminate <b>11</b>. The lead portion <b>24</b><i>a </i>extends toward the positive direction side in the z-axis direction from a region of a longer side of the capacitor portion <b>20</b><i>a </i>on the positive direction side in the z-axis direction, which region is located near an end of the longer side thereof on the negative direction side in the x-axis direction. Thus, the lead portion <b>24</b><i>a </i>extends to the longer side of the ceramic layer <b>16</b> on the positive direction side in the z-axis direction. The lead portion <b>24</b><i>a </i>includes, at its distal end on the positive direction side in the z-axis direction, an exposed portion <b>28</b><i>a </i>that is exposed between two adjacent ceramic layers <b>16</b> at the upper surface S<b>5</b> of the laminate <b>11</b>.

p-0032The capacitor conductor <b>18</b><i>b </i>is disposed on a surface of another ceramic layer <b>16</b> and includes a capacitor portion <b>20</b><i>b </i>and lead portions <b>22</b><i>b </i>and <b>24</b><i>b</i>. The capacitor portion <b>20</b><i>b </i>is substantially rectangular and is arranged inward of outer edges of the ceramic layer <b>16</b> without extending to the outer edges. Further, the capacitor portion <b>20</b><i>b </i>is opposed to the capacitor portion <b>20</b><i>a </i>with the ceramic layer <b>16</b> disposed therebetween. With such an arrangement, an electrostatic capacity is generated between the capacitor portions <b>20</b><i>a </i>and <b>20</b><i>b</i>. The lead portion <b>22</b><i>b </i>extends toward the negative direction side in the z-axis direction from a region of a longer side of the capacitor portion <b>20</b><i>b </i>on the negative direction side in the z-axis direction, which region is positioned near an end of the longer side thereof on the positive direction side in the x-axis direction. Thus, the lead portion <b>22</b><i>b </i>extends to the longer side of the ceramic layer <b>16</b> on the negative direction side in the z-axis direction. The lead portion <b>22</b><i>b </i>is located farther away on the positive direction side in the x-axis direction than the lead portion <b>22</b><i>a</i>. The lead portion <b>22</b><i>b </i>includes, at its distal end on the negative direction side in the z-axis direction, an exposed portion <b>26</b><i>b </i>that is exposed between two adjacent ceramic layers <b>16</b> at the lower surface S<b>6</b> of the laminate <b>11</b>. The lead portion <b>24</b><i>b </i>extends toward the positive direction side in the z-axis direction from a region of a longer side of the capacitor portion <b>20</b><i>b </i>on the positive direction side in the z-axis direction, which region is located near an end of the longer side thereof on the positive direction side in the x-axis direction. Thus, the lead portion <b>24</b><i>b </i>extends to the longer side of the ceramic layer <b>16</b> on the positive direction side in the z-axis direction. The lead portion <b>24</b><i>b </i>is located farther away on the positive direction side in the x-axis direction than the lead portion <b>24</b><i>a</i>. The lead portion <b>24</b><i>b </i>includes, at its distal end on the positive direction side in the z-axis direction, an exposed portion <b>28</b><i>b </i>that is exposed between two adjacent ceramic layers <b>16</b> at the upper surface S<b>5</b> of the laminate <b>11</b>.

p-0033The above-described capacitor conductors <b>18</b><i>a </i>and <b>18</b><i>b </i>are provided on the plurality of ceramic layers <b>16</b> such that they are alternately arranged in the y-axis direction. With such an arrangement, the capacitor C is defined in an area at which the capacitor conductor <b>18</b><i>a </i>and the capacitor conductor <b>18</b><i>b </i>are opposed to each other with the ceramic layer <b>16</b> interposed therebetween.

p-0034The external electrodes <b>30</b><i>a</i>, <b>30</b><i>b </i>preferably include electroconductive layers (first electroconductive layers) <b>12</b><i>a</i>, <b>12</b><i>b </i>(see <figref idrefs="DRAWINGS">FIG. 2</figref>), electroconductive layers (first electroconductive layers) <b>13</b><i>a</i>, <b>13</b><i>b </i>(see <figref idrefs="DRAWINGS">FIG. 2</figref>), electroconductive layers (second electroconductive layers) <b>14</b><i>a</i>, <b>14</b><i>b</i>, and electroconductive layers <b>15</b><i>a</i>, <b>15</b><i>b. </i>

p-0035The electroconductive layers <b>12</b><i>a </i>and <b>12</b><i>b </i>are disposed on the lower surface S<b>6</b> to directly cover the exposed portions <b>26</b><i>a </i>and <b>26</b><i>b</i>, respectively, and are formed by plating and thus made of plated material. The electroconductive layer <b>12</b><i>a </i>is located farther away on the negative direction side in the x-axis direction than the electroconductive layer <b>12</b><i>b</i>. The electroconductive layers <b>12</b><i>a </i>and <b>12</b><i>b </i>are each substantially rectangular and are arranged so as not to extend off of the lower surface S<b>6</b>. The electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are disposed on the upper surface S<b>5</b> to directly cover the exposed portions <b>28</b><i>a </i>and <b>28</b><i>b</i>, respectively, and are formed by plating and thus made of plated material. The electroconductive layer <b>13</b><i>a </i>is located farther away on the negative direction side in the x-axis direction than the electroconductive layer <b>13</b><i>b</i>. The electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are each substantially rectangular and are arranged so as not to extend off the upper surface S<b>5</b>. Preferably, each of the electroconductive layers <b>12</b> and <b>13</b> is made of, for example, at least one kind of metal selected from a group consisting of Cu, Ni, Sn, Pb, Au, Ag, Pd, Bi and Zn, or an alloy including at least one of those metals, and has a thickness in a range of about 1 μm to about 15 μm, for example.

p-0036Preferably, the electroconductive layers <b>12</b><i>a</i>, <b>12</b><i>b</i>, <b>13</b><i>a </i>and <b>13</b><i>b </i>do not include glass.

p-0037Preferably, a metal proportion per unit volume in each of the electroconductive layers <b>12</b><i>a</i>, <b>12</b><i>b</i>, <b>13</b><i>a </i>and <b>13</b><i>b </i>is about 99% or more by weight, for example.

p-0038The electroconductive layer <b>14</b><i>a </i>covers not only at least respective portions of the electroconductive layers <b>12</b><i>a </i>and <b>13</b><i>a</i>, but also portions of the surfaces of the laminate <b>11</b> as illustrated in <figref idrefs="DRAWINGS">FIGS. 1 and 4</figref>, and it is made of a material (sintered metal) including metal and glass. In the electronic component <b>10</b> according to this preferred embodiment, the electroconductive layer <b>14</b><i>a </i>entirely covers the electroconductive layers <b>12</b><i>a </i>and <b>13</b><i>a</i>. More specifically, the electroconductive layer <b>14</b><i>a </i>is arranged such that it covers substantially the entire end surface S<b>3</b> of the laminate <b>11</b> and it is folded at edges of the end surface S<b>3</b> so as to extend over respective portions of the side surfaces S<b>1</b> and S<b>2</b>, the upper surface S<b>5</b>, and the lower surface S<b>6</b>, which are adjacent to the end surface S<b>3</b>. In other words, the electroconductive layer <b>14</b><i>a </i>is arranged to spread in continuously overlapping relation over the lower surface S<b>6</b> defining the mounting surface and the surfaces (i.e., the side surfaces S<b>1</b>, S<b>2</b> and the end surface S<b>3</b>) of the laminate <b>11</b>, which are adjacent to the lower surface S<b>6</b>.

p-0039The electroconductive layer <b>14</b><i>b </i>covers not only at least respective portions of the electroconductive layers <b>12</b><i>b </i>and <b>13</b><i>b</i>, but also portions of the surfaces of the laminate <b>11</b> as illustrated in <figref idrefs="DRAWINGS">FIGS. 1 and 4</figref>, and it is preferably made of a material (sintered metal) including metal and glass, for example. In the electronic component <b>10</b> according to this preferred embodiment, the electroconductive layer <b>14</b><i>b </i>substantially entirely covers the electroconductive layers <b>12</b><i>b </i>and <b>13</b><i>b</i>. More specifically, the electroconductive layer <b>14</b><i>b </i>is arranged such that it covers substantially the entire end surface S<b>4</b> of the laminate <b>11</b> and it is folded at edges of the end surface S<b>4</b> to extend over respective portions of the side surfaces S<b>1</b> and S<b>2</b>, the upper surface S<b>5</b>, and the lower surface S<b>6</b>, which are adjacent to the end surface S<b>4</b>. In other words, the electroconductive layer <b>14</b><i>b </i>is arranged to spread in continuously overlapping relation over the lower surface S<b>6</b> defining the mounting surface and the surfaces (i.e., the side surfaces S<b>1</b>, S<b>2</b> and the end surface S<b>4</b>) of the laminate <b>11</b>, which are adjacent to the lower surface S<b>6</b>.

p-0040The metal component included in each of the electroconductive layers <b>14</b><i>a </i>and <b>14</b><i>b </i>is preferably, for example, one kind of metal selected from a group consisting of Cu, Ni, Ag and Pd, or an alloy including one of those metals. The glass component contained therein is preferably, for example, glass containing B, Si, Ba, Mg, Al, Li, etc. Preferably, each of the electroconductive layers <b>14</b><i>a </i>and <b>14</b><i>b </i>has a thickness of in a range of about 3 μm to about 10 μm, for example.

p-0041As illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref> and the enlarged view in <figref idrefs="DRAWINGS">FIG. 4</figref>, the electroconductive layers <b>15</b><i>a </i>and <b>15</b><i>b </i>are preferably arranged to directly cover the electroconductive layers <b>14</b><i>a </i>and <b>14</b><i>b</i>, respectively, and are formed by plating and are thus made of plated material. Each electroconductive layer <b>15</b> may include a plurality of electroconductive layers. Preferably, each electroconductive layer <b>15</b> is made of, e.g., one kind of metal selected from a group consisting of Cu, Ni, Sn, Pb, Au, Ag, Pd, Bi and Zn, or an alloy including one of those metals, and has a thickness in a range of about 1 μm to about 15 μm, for example.

p-0042The electronic component <b>10</b> having the above-described construction is used in a state mounted to a circuit board. At that time, the electronic component <b>10</b> is mounted to the circuit board such that the lower surface S<b>6</b> is arranged to face the circuit board.

p-0043A method of manufacturing the electronic component <b>10</b> will be described below with reference to <figref idrefs="DRAWINGS">FIGS. 1 to 4</figref>.

p-0044First, predetermined materials are weighed and loaded into a ball mill in which those materials are wet-mixed. The resulting mixture is dried and pulverized. The obtained powder is calcined. The calcined powder is wet-pulverized in a ball mill and dried. The dried powder is disintegrated, whereby dielectric ceramic powder is obtained.

p-0045An organic binder and an organic solvent are added to the dielectric ceramic powder, and they are mixed with one another by using a ball mill. The obtained ceramic slurry is coated in the form of a sheet on a carrier sheet by the doctor blade process and is then dried, thus forming a ceramic green sheet that is to become the ceramic layer <b>16</b>.

p-0046Next, a paste made of an electroconductive material is coated on the ceramic green sheet, which is to become the ceramic layer <b>16</b>, by screen printing or photolithography, for example, whereby the capacitor conductors <b>18</b><i>a </i>and <b>18</b><i>b </i>are formed. The paste made of the electroconductive material is prepared, for example, by adding an organic binder and an organic solvent to metal powder.

p-0047Next, the ceramic green sheets, each of which is to become the ceramic layer <b>16</b>, are laminated to obtain a mother laminate in a state not yet fired. Thereafter, the mother laminate in the state not yet fired is compressed using a hydraulic pressure press, for example.

p-0048Next, the mother laminate in the state not yet fired is cut into a predetermined size to obtain a plurality of laminates <b>11</b> that are not yet fired. The not-yet-fired laminates <b>11</b> are then fired. The firing temperature is preferably, for example, in a range of about 900° C. to about 1300° C. Through the above-described steps, the fired laminates <b>11</b> including the capacitor conductors <b>18</b> are produced.

p-0049Next, the surface of the laminate <b>11</b> is subjected to polishing, such as barrel polishing, for example. With the barrel polishing, the exposed portions <b>26</b><i>a</i>, <b>26</b><i>b</i>, <b>28</b><i>a </i>and <b>28</b><i>b </i>are each exposed at the upper surface S<b>5</b> or the lower surface S<b>6</b> in an increased area than before the barrel polishing.

p-0050Next, the electroconductive layers <b>12</b> and <b>13</b> are formed by plating. More specifically, the laminate <b>11</b> is disposed in a pored barrel in which electroconductive media are loaded. The barrel is then immersed in a plating solution and rotated for a predetermined time. With the rotation of the barrel, the electroconductive media contact the exposed portions <b>26</b><i>a</i>, <b>26</b><i>b</i>, <b>28</b><i>a </i>and <b>28</b><i>b </i>and supply electric power to them. As a result, metals are deposited on the exposed portions <b>26</b><i>a</i>, <b>26</b><i>b</i>, <b>28</b><i>a </i>and <b>28</b><i>b</i>, and the electroconductive layers <b>12</b> and <b>13</b> are formed.

p-0051Next, the electroconductive layers <b>14</b> are formed by the dipping process. More specifically, the laminate <b>11</b> is dipped in an electroconductive paste including metal and glass. The coated electroconductive paste is then fired preferably at a temperature in a range of about 700° to about 900°, for example, thereby forming the electroconductive layers <b>14</b>.

p-0052Next, the electroconductive layers <b>15</b> are formed by plating. More specifically, the laminate <b>11</b> is disposed in a pored barrel in which electroconductive media are loaded. The barrel is then immersed in a plating solution and rotated for a predetermined time. With the rotation of the barrel, the electroconductive media contact the electroconductive layers <b>14</b> and supply electric power to them. As a result, metals are deposited on the electroconductive layers <b>14</b>, and the electroconductive layers <b>15</b> are formed. Through the above-described steps, the electronic component <b>10</b> is produced.

p-0053With the electronic component <b>10</b> described above, the electroconductive layers <b>12</b> and <b>13</b> formed by plating can be effectively prevented from being peeled off from the laminate <b>11</b>. To describe this in more detail, in the multilayer electronic component disclosed in the above-cited International Publication No. 2007/049456, because the external electrodes are formed by plating, they do not include glass. Therefore, the external electrodes of the multilayer electronic component disclosed in the above-cited International Publication No. 2007/049456 are fixed to the laminate with relatively low strength. Thus, the external electrodes are likely to peel off from the laminate in the multilayer electronic component disclosed in the above-cited International Publication No. 2007/049456.

p-0054On the other hand, in the electronic component <b>10</b>, the electroconductive layers <b>14</b> are each preferably made of the material including metal and glass. Therefore, the electroconductive layers <b>14</b> are fixed to the laminate <b>11</b> with a relatively high strength due to the adhesive effect of the glass. Further, the electroconductive layers <b>14</b> are arranged to directly cover at least respective portions of the electroconductive layers <b>12</b> and <b>13</b> that are formed by plating. Accordingly, the electroconductive layers <b>14</b> function to prevent the electroconductive layers <b>12</b> and <b>13</b> from being peeled off from the laminate <b>11</b>. As a result, with the electronic component <b>10</b>, the electroconductive layers <b>12</b> and <b>13</b> can be effectively prevented from being peeled off from the laminate <b>11</b>.

p-0055Further, in the electronic component <b>10</b> according to this preferred embodiment, the electroconductive layers <b>14</b> substantially entirely cover the electroconductive layers <b>12</b> and <b>13</b>. With the electronic component <b>10</b>, therefore, the electroconductive layers <b>12</b> and <b>13</b> can be more effectively prevented from being peeled off from the laminate <b>11</b>.

p-0056Still further, in the electronic component <b>10</b>, the electroconductive layers <b>14</b> are each arranged to extend in continuously overlapping relation over the surfaces of the laminate <b>11</b>, which are adjacent to the lower surface S<b>6</b> defining the mounting surface. Thus, since the electroconductive layers <b>14</b> are each arranged to extend in continuously overlapping relation over the plurality of surfaces, electroconductive layers <b>14</b> are connected to the laminate <b>11</b> with increased strength. As a result, with the electronic component <b>10</b>, the electroconductive layers <b>12</b> and <b>13</b> can be even more effectively prevented from being peeled off from the laminate <b>11</b>.

p-0057In addition, an element size can be reduced with the electronic component <b>10</b>. That point will be described below by comparing an electronic component (called an “ordinary electronic component”) including external electrodes, which are formed by coating an electroconductive paste on end surfaces of a laminate, and the electronic component <b>10</b> with each other.

p-0058In the ordinary electronic component, the external electrodes are formed by immersing the laminate in the electroconductive paste. In that case, the external electrodes are in contact with internal electrodes exposed from the laminate, to thereby establish electrical connection to the internal electrodes. However, because the external electrodes obtained by firing the electroconductive paste is relatively porous, the external electrodes need to be formed with a relatively large thickness to ensure sealing performance that is sufficient to prevent moisture and other contaminants from entering the laminate. Thus, the ordinary electronic component has a problem in that the element size is increased due to the thicknesses of the external electrodes.

p-0059On the other hand, in the electronic component <b>10</b>, the electroconductive layers <b>12</b> and <b>13</b> are formed to directly cover the exposed portions <b>26</b> and <b>28</b> for electrical connection to the capacitor conductors <b>18</b>. Further, the electroconductive layers <b>14</b> are formed to directly cover the electroconductive layers <b>12</b> and <b>13</b>. Since the electroconductive layers <b>12</b> and <b>13</b> are formed by plating, they are made of dense films. Therefore, even with each of the electroconductive layers <b>14</b> each being relatively thin, sufficient sealing performance is ensured with the electroconductive layers <b>12</b> and <b>13</b>. Further, since the electroconductive layers <b>12</b> and <b>13</b> are formed by plating, the electroconductive layers <b>12</b> and <b>13</b> have relatively small thicknesses. Similarly, the electroconductive layers <b>15</b> disposed on the electroconductive layers <b>14</b> are formed by plating and have relatively small thicknesses. Thus, in the electronic component <b>10</b>, the external electrodes <b>30</b> can be formed of the electroconductive layers <b>12</b> to <b>15</b> each being relatively thin. As a result, in the electronic component <b>10</b>, the element size can be reduced as compared to that of the ordinary electronic component.

p-0060An electronic component according to a first modification of a preferred embodiment of the present invention will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 5</figref> is a plan view illustrating an electronic component <b>10</b><i>a </i>according to the first modification while seeing through the electronic component <b>10</b><i>a </i>from above in a laminating direction.

p-0061As illustrated in <figref idrefs="DRAWINGS">FIG. 5</figref>, the capacitor conductors <b>18</b> may preferably not include the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>. With the omission of the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>, the electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are also not required. As a result, the height of the electronic component <b>10</b><i>a </i>in the z-axis direction is reduced.

p-0062An electronic component according to a second modification of a preferred embodiment of the present invention will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 6</figref> is a plan view illustrating an electronic component <b>10</b><i>b </i>according to the second modification while seeing through the electronic component <b>10</b><i>b </i>from above in a laminating direction.

p-0063As illustrated in <figref idrefs="DRAWINGS">FIG. 6</figref>, the electroconductive layers <b>14</b> and <b>15</b> are preferably not disposed on the side surfaces S<b>1</b> and S<b>2</b>, and they have a substantial C-shape when viewed in the y-axis direction. With such an arrangement, the width of the electronic component <b>10</b><i>b </i>in the y-axis direction is less than the width of the electronic component <b>10</b> in the y-axis direction by an amount corresponding to the thicknesses of the electroconductive layers <b>14</b> and <b>15</b>.

p-0064When the electroconductive layers <b>14</b> and <b>15</b> illustrated in <figref idrefs="DRAWINGS">FIG. 6</figref> are formed, only the side surfaces S<b>1</b> and S<b>2</b> need to be masked.

p-0065An electronic component according to a third modification of a preferred embodiment of the present invention will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 7</figref> is a plan view illustrating an electronic component <b>10</b><i>c </i>according to the third modification while seeing through the electronic component <b>10</b><i>c </i>from above in a laminating direction.

p-0066The electronic component <b>10</b><i>c </i>differs from the electronic component <b>10</b><i>b </i>in that the capacitor conductors <b>18</b> do not include the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>, and that the electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are not provided. As illustrated in <figref idrefs="DRAWINGS">FIG. 7</figref>, since the capacitor conductors <b>18</b> do not include the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>, the electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are also not required. As a result, the height of the electronic component <b>10</b><i>c </i>in the z-axis direction is reduced.

p-0067When the electroconductive layers <b>14</b> and <b>15</b> illustrated in <figref idrefs="DRAWINGS">FIG. 7</figref> are formed, only the side surfaces S<b>1</b> and S<b>2</b> need to be masked.

p-0068An electronic component according to a fourth modification of a preferred embodiment of the present invention will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 8</figref> is a plan view illustrating an electronic component <b>10</b><i>d </i>according to the fourth modification while seeing through the electronic component <b>10</b><i>d </i>from above in a laminating direction.

p-0069The electronic component <b>10</b><i>d </i>differs from the electronic component <b>10</b><i>b </i>in that the electroconductive layers <b>14</b> and <b>15</b> cover respective portions of the electroconductive layers <b>12</b> and <b>13</b>. Even in the electronic component <b>10</b><i>d </i>in which the electroconductive layers <b>14</b> and <b>15</b> cover respective portions of the electroconductive layers <b>12</b> and <b>13</b>, the electroconductive layers <b>12</b> and <b>13</b> are also effectively prevented from being peeled off from the laminate <b>11</b>.

p-0070When the electroconductive layers <b>14</b> and <b>15</b> illustrated in <figref idrefs="DRAWINGS">FIG. 8</figref> are formed, only the side surfaces S<b>1</b> and S<b>2</b> and the portions of the electroconductive layers <b>12</b> and <b>13</b> need to be masked.

p-0071An electronic component according to a fifth modification of a preferred embodiment of the present invention will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 9</figref> is a plan view illustrating an electronic component <b>10</b><i>e </i>according to the fifth modification while seeing through the electronic component <b>10</b><i>e </i>from above in a laminating direction.

p-0072The electronic component <b>10</b><i>e </i>differs from the electronic component <b>10</b><i>d </i>in that the capacitor conductors <b>18</b> do not include the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>, and that the electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are not provided. As illustrated in <figref idrefs="DRAWINGS">FIG. 9</figref>, since the capacitor conductors <b>18</b> do not include the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>, the electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are also not required. As a result, the height of the electronic component <b>10</b><i>e </i>in the z-axis direction is reduced from that of the electronic component <b>10</b><i>d </i>in the z-axis direction.

p-0073When the electroconductive layers <b>14</b> and <b>15</b> illustrated in <figref idrefs="DRAWINGS">FIG. 9</figref> are formed, only the side surfaces S<b>1</b> and S<b>2</b> and the portions of the electroconductive layers <b>12</b> and <b>13</b> need to be masked.

p-0074An electronic component according to a sixth modification of a preferred embodiment of the present invention will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 10</figref> is a plan view illustrating an electronic component <b>10</b><i>f </i>according to the sixth modification while seeing through the electronic component <b>10</b><i>f </i>from above in a laminating direction.

p-0075The electronic component <b>10</b><i>f </i>differs from the electronic component <b>10</b> in that the electroconductive layers <b>14</b> and <b>15</b> are not disposed on the end surfaces S<b>3</b> and S<b>4</b>. As a result, the length of the electronic component <b>10</b><i>f </i>in the x-axis direction is reduced as compared to the length of the electronic component <b>10</b> in the x-axis direction by an amount corresponding to the thicknesses of the electroconductive layers <b>14</b> and <b>15</b>.

p-0076When the electroconductive layers <b>14</b> and <b>15</b> illustrated in <figref idrefs="DRAWINGS">FIG. 10</figref> are formed, only the end surfaces S<b>3</b> and S<b>4</b> need to be masked.

p-0077An electronic component according to a seventh modification of a preferred embodiment of the present invention will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 11</figref> is a plan view illustrating an electronic component <b>10</b><i>g </i>according to the seventh modification while seeing through the electronic component <b>10</b><i>g </i>from above in a laminating direction.

p-0078The electronic component <b>10</b><i>g </i>differs from the electronic component <b>10</b><i>f </i>in that the capacitor conductors <b>18</b> do not include the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>, and in that the electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are not provided. As illustrated in <figref idrefs="DRAWINGS">FIG. 11</figref>, since the capacitor conductors <b>18</b> do not include the lead portions <b>24</b><i>a </i>and <b>24</b><i>b</i>, the electroconductive layers <b>13</b><i>a </i>and <b>13</b><i>b </i>are also not required. As a result, the height of the electronic component <b>10</b><i>g </i>in the z-axis direction is reduced from the height of the electronic component <b>10</b><i>f </i>in the z-axis direction.

p-0079When the electroconductive layers <b>14</b> and <b>15</b> illustrated in <figref idrefs="DRAWINGS">FIG. 11</figref> are formed, only the end surfaces S<b>3</b> and S<b>4</b> need to be masked.

p-0080The electronic component according to the present invention is not limited to the above-described preferred embodiment and modifications, and it can be modified without departing from the scope of the present invention.

p-0081While, in each of the electronic components <b>10</b> and <b>10</b><i>a </i>to <b>10</b><i>g</i>, the electroconductive layer <b>14</b> is preferably made of the material including metal and glass, it may preferably be made of a material including metal and resin. Stated another way, the electroconductive layer <b>14</b> may preferably be made of an electroconductive resin including a metal filler and resin. The metal filler may preferably be made, for example, of one kind of metal selected from a group consisting of Cu, Ni, Ag and Pd, or an alloy including one of those metals. Alternatively, coated powder, such as Cu powder coated with Ag, may preferably be used as the metal filler. The resin may preferably be, for example, a thermosetting resin, such as an epoxy resin or a phenol resin.

p-0082When the electroconductive layer <b>14</b> is made of the material including metal and resin, the resin is softened during thermal setting, and the softened resin enters concave spots in the surfaces of the electroconductive layers <b>12</b> and <b>13</b> and concave spots in the surfaces of the laminate <b>11</b>. As a result, in each of the electronic components <b>10</b> and <b>10</b><i>a </i>to <b>10</b><i>g</i>, the electroconductive layers and <b>13</b> can be more effectively prevented from being peeled off from the laminate <b>11</b> due to the anchoring effect or the chemical adsorption force of the resin. The thermosetting temperature of the electroconductive layer <b>14</b> is preferably in a range of about 200° C. to about 300° C., for example.

p-0083An electronic component <b>10</b><i>h </i>according to another preferred embodiment of the present invention, which preferably includes the electroconductive layers <b>14</b> each made of the material including metal and resin, will be described below with reference to the drawing. <figref idrefs="DRAWINGS">FIG. 12</figref> is a plan view illustrating the electronic component <b>10</b><i>h </i>according to this preferred embodiment while seeing through the electronic component <b>10</b><i>h </i>from above in a laminating direction.

p-0084As illustrated in <figref idrefs="DRAWINGS">FIG. 12</figref>, the capacitor conductors <b>18</b> may preferably omit the lead portions <b>22</b><i>a </i>and <b>22</b><i>b</i>. With the omission of the lead portions <b>22</b><i>a </i>and <b>22</b><i>b</i>, the electroconductive layers <b>12</b><i>a </i>and <b>12</b><i>b </i>are also not required. As a result, the height of the electronic component <b>10</b><i>h </i>in the z-axis direction is reduced.

p-0085Further, in the electronic component <b>10</b><i>h</i>, cracking attributable to flexing of a circuit board can be effectively prevented as described below. In the ordinary electronic component, because of the relatively hard external electrodes being fixed to the laminate, when the circuit board is mounted or when thermal shock cycles are applied to the circuit board, the circuit board is flexed and stress is exerted on the laminate in the electronic component and on solders for establishing the connection. Consequently, the laminate and the solders may be cracked. Thus, there is a risk that the occurrence of a crack may cause a short-circuit fault or an open-circuit fault.

p-0086On the other hand, in the electronic component <b>10</b><i>h</i>, since the electroconductive layers <b>14</b><i>a </i>and <b>14</b><i>b </i>are each made of the material including metal and resin, they are relatively soft. Therefore, when the circuit board is flexed, the electroconductive layers <b>14</b><i>a </i>and <b>14</b><i>b </i>are peeled off from the laminate <b>11</b>, respectively, at an end (denoted by D in <figref idrefs="DRAWINGS">FIG. 12</figref>) of the electroconductive layer <b>14</b><i>a </i>on the lower surface S<b>6</b>, which end is located relatively on the positive direction side in the x-axis direction, and at an end (denoted by D in <figref idrefs="DRAWINGS">FIG. 12</figref>) of the electroconductive layer <b>14</b><i>b </i>on the lower surface S<b>6</b>, which end is located relatively on the negative direction side in the x-axis direction. Thus, cracking attributable to the flexing of the circuit board can be effectively avoided in the electronic component <b>10</b><i>h</i>. Even when the electroconductive layers <b>14</b><i>a </i>and/or <b>14</b><i>b </i>is peeled off from the laminate <b>11</b> at D in <figref idrefs="DRAWINGS">FIG. 12</figref>, a current path extending from the electroconductive layer <b>14</b> to the capacitor conductors <b>18</b> through the electroconductive layer <b>13</b> is ensured, whereby an open-circuit fault does not occur in the electronic component <b>10</b><i>h. </i>

p-0087While, in each of the electronic components <b>10</b> and <b>10</b><i>a </i>to <b>10</b><i>h</i>, the electroconductive layers <b>12</b> and <b>13</b> are preferably formed by barrel plating that is one type of electroplating, they may also be formed by electroless plating, for example.

p-0088While, in each of the electronic components <b>10</b> and <b>10</b><i>a </i>to <b>10</b><i>h</i>, the laminate <b>11</b> preferably includes the capacitor C, it may include other electronic elements, such as a coil and a resistance, for example.

p-0089As described above, preferred embodiments of the present invention are effectively applied to an electronic component and are especially superior in effectively preventing the external electrodes, which are formed by plating, from being peeled off from the laminate.

p-0090While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.